Volume 9 (2007): Issue 2 (June 2007)

A mathematical model enabling a quantitative description of wet oxidation of excess sludge in continuous bubble columns is proposed. The model consists of mass and heat transfer kinetic equations and material and heat balance equations of gas and liquid phases flowing through the absorber. The equations of material and heat balance refer to a parallel, co- current flow of gas and liquid phase and take into account a complex chemical reaction in the liquid phase core. The proposed model was used in a numerical simulation of wet oxidation in a bubble absorber for different process conditions: flow rate and composition of the gas and liquid phase, temperature and pressure, and different heights and diameters of the column.

The present paper discloses a novel photoreactive solvent-free acrylic pressure-sensitive adhesive (PSA) systems, especially suitable for the so much adhesive film applications as the double-sided, single-sided or carrier-free technical tapes, self-adhesive labels, protective films, marking and sign films and wide range of medical products. The novel photoreactive solvent-free pressure-sensitive adhesives contain no volatile organic compounds (residue monomers or organic solvent) and comply with the environment and legislation. The synthesis of this new type of acrylic PSA is conducted in common practice by solvent polymerisation. After the organic solvent are removed, there remains a non-volatile, solvent-free highly viscous material, which can be processed on a hot-melt coating machine at the temperatures of about 100 to 140°C.

Two groups of acrylamide copolymers have been obtained by inverse microemulsion polymerization using: (i) acrylamide (AAm) with [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETAC) in the presence of sodium montmorillonite (MMT), and (ii) acrylamide with acrylic acid (AA) in the presence of aluminum sulphate. The received materials were characterised by capillary viscometry and the DSC methods, as well as the flocculation performances of the modified copolymers in the treatment of aqueous model suspensions of talc and calcium montmorillonite have been investigated. The effectiveness of the acrylamide flocculants was evaluated on the basis of the suspension extinction reduction and the sludge volume. The obtained results have been compared while using the modified materials and appropriate anionic and cationic AAm copolymers.

The possibility of potential application of membrane distillation for the concentration of waste salt solutions has been presented in this work. It was found that the oxidation of iron compounds takes place during the process that was associated with the formation of a layer of oxides on the membrane surface. A fast decline of the permeate flux was observed due to the scaling phenomena. The problem of scaling was eliminated by the acidification with H₂SO₄ of the feed to the pH value of 2.

In this paper the results of investigation of magnesium removal from raw zinc concentrate have been presented. The raw materials derive from ZG Trzebionka and ZGH Bolesław. The differences in zinc and magnesium contents are characteristic of these materials. The experiments were carried out in the periodical reactor at 25°C using the H₂SO₄ solution of 20, 50, and 70%(v/v) concentration. The weight ratio of the solid phase to the liquid phase was 1:10 and 1:2. On the basis of the experimental results it can be stated that the application of sulphuric(VI) acid leaching permits to increase the zinc yield in Zn-Pb ore processing. This method permits to obtain zinc concentrate containing more than 60% Zn and MgO below 0.3% and CaO about 1.4%.

The influence of urea on the vanadium(V) and potassium ion concentrations in the KHCO₃ + NH₄VO₃ + H₂O system was determined in the temperature range of 293 K to 303 K. Additionally, the solution density dependence versus the urea concentration was presented. These data are essential for the assessment of optimum operating conditions for the new production process of potassium carbonate.

Studies were conducted on the production of chromium(III) silicates, the green pro-ecological pigments. The pigments were precipitated from sodium silicate and chromium(III) sulphate solutions in the system of two emulsions prepared in hexane in the presence of a non-ionic surfactant as an emulsifier. The chromium(III) sulphate represented a reduction product of chromate(VI) compounds present in post-galvanic wastes. The reduction agent involved metanal in an acidic medium. The obtained products were subjected to a comprehensive physicochemical analysis, their dispersive and morphological properties were determined. The precipitated green products exhibiting intense colour, were uniform and their particles manifested a low tendency to form agglomerate structures.

A pseudo-second order rate equation describing the kinetics of the adsorption of 1,2-dichloropropane from aqueous solution onto the activated carbon at different initial concentrations, adsorbent dose, temperature, particle diameter and the rate of stirring have been developed. The rate constant was calculated. The rate constant correlation in a good mixing conditions was described as a function of the temperature.

In this study dependences of the adsorption equilibrium of 1,2-dichloropropane in aqueous solution for six activated carbons (A, AG, AG5, DTO, WD-ekstra, CWZ-22) and four polymeric adsorbents (XE-563, XE-572, XE-340, XE-348) were presented. All the adsorption isotherms onto activated carbons were described by the Freundlich equation. To analyze the isotherms on the polymeric adsorbents the Langmuir-Freundlich equation was used. It was found that in the low range of the concentrations the adsorptive properties of the activated carbons are reduced in the following direction DTO>WD-ekstra>CWZ-22>AG>A>AG5. Reducing the adsorptive properties of the polymeric adsorbents states was carried out in the following order: XE-340> XE-572>XE-563>XE-348. The adsorbents XE-340, XE-572 and XE-563 have much more higher adsorptive properties than the applied activated carbons. Lower adsorptive properties of XE-348 are the result of its high surface polarity.

The scope of this contribution was to investigate in detail an application of fly ash adsorbent for the removal of arsenite ions from à dilute solution. The experiments have been carried out using fly ash from black coal burning power plant "Siersza" and brown coal burning power plant "Turów" (Poland), which was wetted, then mixed and tumbled in the granulator with a small amount of cement to increase the mechanical strength of agglomerates. The measurements of arsenic adsorption from the aqueous solution were carried out in the flask (with shaking), as well as in the column (with circulation), in order to compare two different methods of contacting waste with adsorbent. The adsorption isotherms of arsenic were determined for granulated material, using the Freundlich model. Kinetics studies indicated that the sorption follows a pseudo-first-order (PFO) model (Lagergren) and the Elovich-type model.

Facing the still growing demand for metals, particularly for zinc, the recovery of metals from secondary sources should be considered. Spent pickling solutions can be the source of valuable products such as hydrochloric acid, zinc or iron salts or even metallic zinc. The selection of an efficient, selective and economical method for the regeneration of such solutions is a key issue for hot dip galvanizing plants, especially in reference to strict environmental protection regulations.

Determination of trace elements in combusted materials has always been an interesting field of environmental studies. Particulate matter, in particular, is a serious problem which, can lead to air pollution especially by heavy metals emissions in urban and industrial areas. There is a considerable concern about the elevated level of mercury released during combustion and the proportion of anthropogenic mercury in the environment. Nowadays, small-scale installations have been identified as a significant source-pathway for mercury pollution, particularly those that use coal. A total amount of mercury was determined using Mercury Analyzer. The investigated material consists of bottom ash, fly ash, slag, soot or dust. The obtained results varied according to the type of the material and plant. The developed methodology was checked by carrying out the analysis of certificate material of Soil NCS ZC 73001 and the reference material of Soil-7.

The results of 1-butene-3-ol (1B3O) epoxidation over the titanium silicalite catalysts: TS-1, Ti-Beta, Ti-MCM-41 has been presented. The optimal parameters obtained for the individual catalyst were compared. The main functions describing the process were: the selectivity of transformation to 1,2-epoxy-3-butanol (1,2E3B) in relation to 1B3O consumed, the conversions of 1B3O and hydrogen peroxide and the selectivity of the transformation to organic compounds in relation to the H₂O₂ consumed. The main product of the epoxidation process was 1,2-epoksy-3-butanol, the chemical compounds having a lot of applications.

The investigations of 1-buten-3-ol (1B3O) epoxidation by 30% hydrogen peroxide over Ti-Beta catalyst were performed. The experiments were carried out under the autogenic pressure and at the presence of methanol as a solvent. The influence of the following technological parameters on the course of epoxidation: temperature (20 - 120°C), the molar ratio of 1B3O/H₂O₂ (0.5:1 - 5:1), methanol concentration (5 - 90 wt%.), Ti-Beta concentration (0.1 - 5.0 wt%) and the reaction time (0.5 - 5.0 h) was investigated. The main functions describing the process were: the selectivity of transformation to 1,2-epokxy-3-butanol in relation to 1B3O consumed, conversions of substrates as well as the selectivity of transformation to organic compounds in relation hydrogen peroxide consumed.

According to sustainable development principles, searching for alternative phosphorus sources, especially possible ways of its recycling from waste, should be treated as a preferential problem of the phosphorus industry. The ways admitted as most important are:

- phosphorus recovery from municipal and industrial sewage and from sewage sludge,

- utilization of phosphorus from manure

- management of waste from meat industry

The forecasts elaborated at the end of the last century, indicate that over 50% of the world phosphorus resources in use today will be depleted during the next 60 - 70 years. That fact contributes to increase of market prices of phosphorus products.

This work presents possible directions for the recovery and management of sewage sludge, meat meal and manure as a phosphorus source for chemical industry.

Tetrachloromethane (TCM) and 1,1,2,2-tetrachloroethane (TChE) were oxidized in the temperature range from 300 to 600°C and at contact time of 0.36 s. The following catalysts were applied during the process: the granular one - platinum (0.12%) at the TiO₂-SiO₂ carrier, platinum ZChO-80 (0.15%) at γ-Al₂O₃ carrier, palladium (1%) at γ-Al₂O₃ carrier and monolithic platinum-rhodium catalyst (Pt - 0.09% and Rh - 0.04%) at the cordierite carrier.

The substrates were oxidized in the presence of the above mentioned catalysts with various efficiencies depending on the molecular structure and the type of the catalyst. Palladium contact appeared to be the most active among the others. In the presence of this catalyst, total oxidation of TCM and TChE proceeded at the temperature of 425 and 500°C, respectively. The content of PCDD/Fs in gaseous products obtained during the oxidation of both substrates, was significantly lower than the admissible value of the toxicity equivalent (0.1 ng TEQ/m³).

This paper reports studies on the influence of vanadium concentration on the catalytic activity of DESONOX catalysts (in DESOX reaction) based on modified montmorillonite from Jelsovy Potok. The investigation of the influence on the physicochemical properties of the catalysts on their behaviour has also been studied.

In these studies we attempted to evaluate the lipolytic, proteolytic and cellulolytic activity of bacterial strains isolated from water and the bottom sediments of Turawa Lake. The following bacterial genera prevailed among the isolated strains: Bacillus, Pseudomonas, Enterobacter, Cellulomonas and Cytophaga. The lipolytic activity was determined using a titrimetric method, the proteolytic activity — using a modified Anson method, and the cellulolytic activity - on the basis of mass decrement of a cellulose disk after 14 days of bacterial culture. The cultures were maintained at 28°C, pH 7.0 with the following substrates: olive oil, albumin and cellulose disk. Among the analysed microorganisms, Bacillus and Pseudomonas strains showed the highest lipolytic and proteolytic activity. In the cellulolytic assay Cytophaga bacteria showed about twofold higher activity than that of Celulomonas.

In this work we tested biopreparations developed in our laboratory for their ability to degrade the organic matter of the bottom sediments of Turawa Lake. The biodegradation was conducted under laboratory conditions for 6 weeks. For the testing purposes, there were three variants of biopreparations that contained autochthonous strains originating from our own collection and their mixture. The testing showed that the introduction of the biopreparations to the bottom sediment resulted in a significant increase of the number of bacteria, which consequently brought about the reduction of organic compounds in the sediment. In the case of all the variants, the number of bacteria increased by order of 10² - 10⁴ CFU/g after 42 days of biodegradation. Among the tested biopreparations, the most effective one was the mixture of the autochthonous strains and those originating from the collection. After biopreparation was applied, a drop of content of carbohydrates by 66.94%, fatty matter by 83.33% and proteins by 74.42% was noted.

In a two-factor pot experiment impact of two doses of six types of composts prepared from the municipal sewage sludge with an addition of canteen waste, wheat straw and cocoa husk on the total number of bacteria, actinomycetes and fungi in the soil were exmined. The light soil used in the experiment was taken from the Ap level of an arable field. On all the objects with composts there was mineral NPK fertilization applied, the control object was fertilized with the NPK only. The test plant was grass Festulolium which was harvested three times and after the third cut the samples of the soil were taken for microbiological analyses.

The conducted research shows that the number of microorganisms in soil was dependent on the dose and the type of the compost. The second dose of the compost, in comparison with the control object, in most composts considerably increased the number of bacteria and the first dose increased the number of actinomycetes. However, the number of fungi, in most cases, with both doses of composts, was lower than in the soil from the control object. The highest number of bacteria was noticed on the object with the co-most prepared from 35% sewage sludge + 35% canteen waste + 30% straw and actinomycetes on the object with the compost prepared from 35% sewage sludge + 35% canteen waste + 30% cocoa husk. The development of the soil fungi was restrained in the highest degree by the first dose of the compost prepared from 35% sewage sludge + 35% canteen waste + 15% straw + 15% cocoa husk and by the second dose of the compost prepared from 70% sewage sludge + 30% straw.

Immobilization of heavy metals in the waste with the use of cement matrix has been investigated. The quality of the obtained granulated products has been assessed and the possible areas of application have been indicated.

In a one-year pot experiment the effect of waste elementary sulphur on the following parameters was observed: 1. on the chemical composition of mustard plants during the growing season, 2. on the yield of seeds, straw and oil, 3. on the chemical composition of seeds and 4. on the content of the water-soluble sulphur in the soil after the harvest.

Elemental sulphur was obtained as a waste material of petroleum refining and was incorporated into a 15-15-15 NPK fertiliser where it comprised 4%. The experiment had the following variants: 1) control (unfertilised); 2) NPK 1; 3) NPK 2; 4) NPKS 1; 5) NPKS 2. The smaller dose amounted to 3.3 g, the higher one to 6.7 g of the fertiliser per pot (6 kg of soil). Moreover all variants were performed in 2 different soils - a medium soil with neutral pH value and a heavy one with alkali pH value.

At the stage of 6 true leaves, the content of nitrogen in plants increased in accordance with its dose. Simultaneously, sulphur applied in the NPKS fertiliser improved nitrogen utilization. The difference between the variants fertilised with NPK and the variants with NPKS amounted to 38.9% in the neutral medium soil, whereas in the alkali heavy soil it was as low as 1.4%.

The yield of both seed and straw in the fertilised variants was statistically significantly higher than in the unfertilised control variant. However, there were observed no statistically significant differences between the variants with sulphur and the variants without sulphur although both the yield of the seed and straw in the variants with NPKS was higher than in the variants with NPK.

The application of elemental sulphur into the neutral medium soil increased the concentration of both nitrogen and sulphur in the mustard seed in comparison with the variants fertilised with NPK only. The difference between them comprises 1.8% and 9.0% in variants with the small and high dose, respectively. In the heavy soil, the trend was opposite.

The application of sulphur into both soils resulted in the increase of the oil content in comparison with the NPK variants.

Sulphur addition to NPK had a positive impact on the augmentation of the available sulphur content in the soil which can positively affect, particularly the following crops. Still, a drop in the pH value was not confirmed.

The paper reveals the results of the research on the reverse osmosis recovery of zinc from galvanic electroplating. The pilot plant tests were performed in an electroplating shop. Raw washings were concentrated with a spiral wound 2.5x40" module with a composite polymeric membrane.

The research tests have proved that the proposed RO process enables successful concentration of the nonferrous metal in raw washings. The retentate of the RO process has contained about 96% of the metal previously wasted in washings discharged to the environment. The retentate can be recycled to the mother electroplating process. The permeate of the RO process can be recycled to the washing system of the electroplating shop.

The removal of azo dye Acid Red 18 in hybrid photocatalysis/membrane processes systems was investigated. The photocatalytic reactions were conducted in the reactor with photocatalyst suspended in the solution. The reaction solution was recirculated through the ultrafiltration system. A commercially available titanium dioxide (Aeroxide® P25, Degussa, Germany) was used as a photocatalyst. The solution after the photocatalytic/UF reaction was applied as the feed for the membrane distillation process. The changes of various parameters, including the concentration of the dye, pH and the conductivity of the solution, TOC and TDS content were analyzed during the process.

It was found that azo dye Acid Red 18 could be successfully decolourised in the hybrid photocatalysis/UF system. The catalyst particles were retained in the feed solution by means of the ultrafiltration membrane so the obtained permeate was free of TiO₂. The application of ultrafiltration together with the photocatalytic process results in the separation of photocatalyst from the treated solution but does not give the complete removal of organic matter from the reaction mixture. Membrane distillation applied with the permeate after the photocatalysis/UF process as a feed gives a complete separation of TOC from the treated solution and the obtained product is practically pure water.

The extraction of palladium(II) from hydrochloric acid solutions of various concentrations in the presence of different amounts of sodium chloride with phosphonium ionic liquid Cyphos®IL101 in toluene was investigated. The extraction of Pd(II) is very effective. The percentage extraction of Pd(II) from 0.1 mol dm- 3 HCl solution amounts to 97% with Cyphos®IL101. Both the increase in HCl concentration and the presence of NaCl have a negative influence on the extraction. The extent of extraction from 0.1 mol dm-3 HCl solution in the presence of 0.5 mol dm^-3 NaCl is about 80% and from 3 mol dm^-3 HCl is lower and amounts to 56%. The extraction of Pd(II) from aqueous 0.1 mol dm^-3 HCl and from 0.1 mol dm^-3 HCl in the presence of 0.5 mol dm^-3 NaCl with this phosphonium ionic liquid is rapid and the equilibrium is achieved after 1 - 2 minutes. The extraction of Pd(II) from aqueous 3 mol dm^-3 HCl is slower and the equilibrium is achieved after 5 - 6 minutes.

The possibility of obtaining sorbents with a good sorption capacity from miscanthus has been investigated. The chars and the activation products were obtained from the miscanthus in a rotary furnace. The activation process of miscanthus was carried out by water vapour at 700-800°C and at the activation time of 30-90 min. We found that the optimum conditions for the activation process were: the activation temperature of 750°C (activation time of 60 and 90 min) and 800°C (activation time of 45 or 60 min). For these conditions the sorbents with the best sorption capacity for p-chlorophenol, toluene, methylene blue and Congo red were obtained.

The mass transfer rates during CO₂ absorption and desorption from N-methyl-2-pyrrolidone solutions were measured at 293.15 K in a baffled agitated reactor with a flat gas-liquid interface. Based on the measured values of pressure changes, the desorption rate was determined and compared to the absorption rate at the same driving force. Two distinct mechanisms of desorption were observed. The transition from bubbling to the diffusive desorption is found to be a function of the supersaturation ratio, pressure and the stirring speed.

The results of 1-buten-3-ol (1B3O) epoxidation with 30% hydrogen peroxide over the Ti-Beta catalyst were presented. The studies were performed under the atmospheric pressure and at the presence of methanol as a solvent. There was examined the influence of the following parameters: the temperature (0 - 60°C), the molar ratio of 1B3O/H₂O₂ (1:1 - 5:1), methanol concentration (5 - 90 wt%), the Ti-Beta catalyst concentration (0.1 - 5.0 wt%) and the reaction time (0.5 - 5.0 h). The optimal parameters were determined by using the following functions: the selectivity of the transformation to 1,2-epoxy-3-butanol (1,2E3B) in relation to 1B3O consumed, the selectivity of the transformation to organic compounds in relation to hydrogen peroxide consumed, the conversions of 1B3O and hydrogen peroxide. The main product of epoxidation was 1,2-epoxy-3-butanol, epoxide having several applications.